American fern journal - American Fern Society. (American Fern Society, 1960)

American fern journal - American Fern Society. (American Fern Society, 1961)

American fern journal - American Fern Society. (American Fern Society, 1962)

American fern journal - American Fern Society. (American Fern Society, 1963)

American fern journal - American Fern Society. (American Fern Society, 1964)

American fern journal - American Fern Society. (American Fern Society, 1965)

American fern journal - American Fern Society. (American Fern Society, 1966)

American fern journal - American Fern Society. (American Fern Society, 1967)

American fern journal - American Fern Society. (American Fern Society, 1968)